Patent GB-651525-A (GB)
Title: Processes for treating ores and similar mixtures containing water-soluble salts
IPC: C01D3/08
Filed: 1948-03-12
Abstract: A process of treating ores containing water soluble salts and similar mixtures containing water-soluble salts by circulating a saturated salt solution through a plurality of treatment stages and separating a purified salt therefrom, includes the steps of washing the separated salt with water, heating a portion of the wash water to evaporate a fraction of the same and to form a salt sludge, returning the sludge to the solution at an intermediate treatment stage and returning the remaining portion of the wash water solution not subjected to heating, to the initial stage of the process.  The solution remaining after separation of salt is returned to the initial stage and wash water remaining from washing the separated salt may be added to the returning solution. Sufficient water may be used to remove all solution from the salt and the sludge remaining after evaporation of the wash water is added to a treatment stage ahead of the final stage, the total quantity of water circulating remaining substantially the same. In the treatment in which the saturated solution contains two soluble salts such as sodium chloride and potassium chloride separate solid masses of the two salts are formed and are washed, the wash water from both masses being added to the solution from the final separation stages of the two salts.  An undesired salt may be removed and concentrated by flotating, thickening and filtration, the desired salt being filtered from the remaining solution.  The combination of wash water and circulating solution may be heated to reduce its water content, e.g. by introducing a combustible mixture below the surface of a portion of the solution, burning the mixture and allowing the hot gases to transfer heat to the solution while bubbling through it, whereby water is evaporated and a salt sludge is formed.  The amount of water evaporated is preferably such as to produce a sludge of one salt while the other is retained in solution.  The process may be employed in the flotation separation of potash, borax, sodium, sulphate and potassium nitrate from their ores.ALSO:A process of treating ores containing water soluble salts and similar mixtures containing water soluble salts by circulating a saturated salt solution through a plurality of treatment stages, and separating a purified salt therefrom, includes the steps of washing the separated salt with water, heating a portion of the wash water to evaporate a fraction of the same and to form a salt sludge, returning the sludge to the solution at an intermediate treatment stage and returning the remaining portion of the wash water solution not subjected to heating, to the initial stage of the process.  The solution remaining after separation of salt is returned to the initial stage and wash water remaining from washing the separated salt may be added to the returning solution.  Sufficient water may be used to remove all solution from the salt and the sludge remaining after evaporation of the wash water is added to a treatment stage ahead of the final stage so that the total quantity of water remains substantially the same. In the treatment in which the saturated solution contains two soluble salts such as sodium chloride and potassium chloride, separate solid masses of the two salts are formed and are washed, the wash water from both masses being added to the solution from the final separation stages of the two salts.  An undesired salt may be removed and concentrated by flotation, thickening and filtration, the desired salt being filtered from the remaining solution.  The combination of wash water and circulating solution may be heated to reduce its water content, e.g. by introducing a combustible mixture below the surface of a portion of the solution, burning the mixture and allowing the hot gases to transfer heat to the solution while bubbling up through it whereby water is evaporated and a salt sludge is formed.  The amount of water evaporated is preferably such as to produce a sludge of one salt while the other is retained in solution.  The process may be employed in the flotation separation of potash, borax, sodium sulphate and potassium nitrate from their ores.